#include <bits/stdc++.h>
using namespace std;
/* typedef */
typedef long long ll;
typedef pair<int, int> pii;
/* constant */
const int INF = 1 << 30;
const ll LINF = 1LL << 61;
const int NIL = -1;
const int MAX = 10000;
const int mod = 1000000007;
const double pi = 3.141592653589;
/* global variables */
/* function */
/* main */
int main(){
    int n;
    cin >> n;
    int ans = 0;
    for (int tr = 0; tr * 5 <= n; tr++) {
        int r = n - tr * 5;
        // cvの回数はtry以下
        for (int cv = 0; cv <= tr && cv * 2 <= r; cv++) {
            int penalty = r - cv * 2;
            // 残りが3の倍数ならpenaltyキックで得点可能
            if (penalty % 3 == 0) ans++;
        }
    }
    cout << ans << '\n';
}